skiing

package noj_skiing;

import java.util.*;
import java.math.*;

public class Main {

    public static void main(String[] args) {
        Solution s = new Solution();
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int[] result = new int[N];
        for(int i = 0; i < N; i++) {
            int rowNum = sc.nextInt(); 
            int colNum = sc.nextInt();
            int[][] info = new int[rowNum][colNum];
            for(int r = 0; r < rowNum; r++) {
                for(int c = 0; c < colNum; c++) {
                    info[r][c] = sc.nextInt();
                }    
            }
            result[i] = s.getResult(info, rowNum, colNum);
        }
        sc.close();
        for(int i : result) {
            System.out.println(i);
        }
    }

}
class Solution {
    public int getResult(int[][] info, int rowNum, int colNum) {
        int max = 0;
        int[][] states = new int[rowNum][colNum]; //make sure equal 0 all
        for(int r = 0; r < rowNum; r++) {
            for(int c = 0; c < colNum; c++) {
                max = Math.max(max, getMaxLength(info, r, c, rowNum, colNum, states));
            }    
        }
        return max;
    }
    public int getMaxLength(int[][] info, int row, int col, int rowNum, int colNum, int[][] states) {
    
        if(row < 0 || row >= rowNum || col < 0 || col >= colNum) //如果输入的坐标越界的处理
            return 0;
        if(states[row][col] != 0) //所求位置的最大长度求过
            return states[row][col];
        
        int nextStep = findNextStep(info, row, col, rowNum, colNum);
        if(nextStep == 0) //所求位置在队尾
            return states[row][col] = 1;
        int maxLengthUp     = (nextStep & 8) == 8 ? getMaxLength(info, row - 1, col, rowNum, colNum, states) : 0;
        int maxLengthDown     = (nextStep & 4) == 4 ? getMaxLength(info, row + 1, col, rowNum, colNum, states) : 0;
        int maxLengthLeft     = (nextStep & 2) == 2 ? getMaxLength(info, row, col - 1, rowNum, colNum, states) : 0;
        int maxLengthRight     = (nextStep & 1) == 1 ? getMaxLength(info, row, col + 1, rowNum, colNum, states) : 0;
                
        return max_4(maxLengthUp, maxLengthDown, maxLengthLeft, maxLengthRight) + 1;
    }
    public int findNextStep(int[][] info, int row, int col, int rowNum, int colNum) {
        int result = 0;
        
        if(row != 0 && info[row - 1][col] < info[row][col])             //up
            result |= 8;
        if(row != rowNum - 1 && info[row + 1][col] < info[row][col])     //down
            result |= 4;
        if(col != 0 && info[row][col - 1] < info[row][col])             //left
            result |= 2;
        if(col != colNum - 1 && info[row][col + 1] < info[row][col])     //right
            result |= 1;
        
        return result;
    }
    public int max_4(int i_1, int i_2, int i_3, int i_4) {
        return Math.max(Math.max(i_1, i_2), Math.max(i_3, i_4));
    }
}

感觉不是很难，思路一上来就可以想出来，具体一些细节的处理也没有很坑的地方。